Apparatus for cutting metal tubes



July 29 1941- F. GRIEDER Y 2,250,931

` APPARATUS FOR CUTTING METAL TUBES 47 85 i 2,0 99 76 J- 89 95 l?? 25 o v- ,24 I 46 k W fw i j 77 Arney July 29, 1941. F. GRIEDER 2,250,931

APPARATUS FOR CUTTING METAL TUBES Filed Maron 1, Y1940 2 sheets-sheet 2 l 13/ A A 52- 74 34 6 11152 16 /EJ /v J0 j; 105 5 35J h 6.a' 64 63 Y Amey,

Patented July .29,

UNITED STATES PATENT OFFICE I APrARATUs magma METAL 'ruinasA Fred Grieder, Detroit, Mich.

Application Mai-n 1, 1940, sel-lama. 321,613

(ci. 164-49) I 14 Claims.

This invention relates to a tube cutting punch and die mechanism whereby a metallic or similar tube may be cut by means of punches and dies located entirely on theoutside of the tube.

The operation of cutting metal'tubing into pieces of suitable lengths presents a serious problem in many industries wherein apparatus containing such tubing is being manufactured. Several methods for cutting such tubing have ,been devised, all of them unsatisfactory when thin tubing of large diameter is being cut. Such tubing is`often cut in a lathe, while an ordinary lathe tool is used to cut it into two pieces. process produces an inside burr, unless expensive and inconvenient means are resorted to to prevent it and is also objectionable, becauseof the tendency of the tube to whip when the long lengthsare beingcut oil. To aviod the latter objection, tubing is often cut in a shear which causes a complete collapse of the tube at the point of cutting. It is then turned in a lathe and a small portion of the tube is removed from the cut end leaving a fairly smooth end. Saws are also used to some extent for cutting such tubing, but a saw produces burrs both on the inside and outside of the tube and leaves a. rough end.

In order to overcome the diicu1ties,I have devised a combination punch and die mechanism suitable for use in an ordinary punch press which cuts a piece of tubing at any point along its length, regardless of the distance of the desired cut from either .end of the tube, by the use of a plurality of dies and punches. In the preferred modification of my invention,`the tube is held tightly by a plurality of dies all around its circumference adjacent to the point at which the cut is to be made, and while so held a punch is forced throughthe tube at a very acute angle. This causes a hole to be cut in one side of the tube, and I have found that such an arrangement leaves substantially no burr or roughness along the edges which will eventually be part of the finished end of the tube. When this operation is completed another punch can be forced into the hole so formed and used to exert a shear- -ing force against the edges of the die holding from the outside. This second cut will not leave any burr or rough edge either, and this method has the distinct advantage that it is unnecessary to have any plug die or any other metal object on the inside of the tube when the opening cut is made.

It is, therefore, ,an `important object of Amy present invention to provide a punch and die mechanism which will cut a piece of tubing in This such amanner as to leave a smooth, burr free end.

It is a further object of this invention to pro-- vide a punch and die mechanism :for cutting tubing twhich will cut the tubing with a minimum of was e.v

It is a further object of my invention to provide a tube cutting mechanism adapted for use in a punch press.

It is a further object of'my invention to providea tube cutting mechanism adapted to cut metallic and similar' tubes by means of a system of punches and dies which operate Without reference to the ends of the tube.

Itis a further object of this invention to provide a process for cutting tubing in which the above disclosed objectives are accomplished.

Other and further objects of this invention will be evident from the following specication and claims, and from the accompanying drawings.

As shown on the drawings: Figure 1 is a cross section of my invention taken throughthe middle of the punches, with,

parts shown in elevation.

Figure 2 is a plan view of the, bottom plate of my combination tube cutting die,.showing the location of certain openings.

Figure 3 is a cross section of a portion of 'my invention showing certain parts broken away,- and taken along the line III-III of Figure. 1.

Figure 4 is a plan'view showing-the top surface of the dies from theapparatus shown in Figure 1.

Figure 5 shows an elevational Niew of the linside surfaces of two of the dies shown in Figure 4 and a portion of one of the punches, the tube being cut being illustrated in cross section.

Figure 6 shows lthe second punch with a part broken away just as it is` in the actof entering the tube, through the opening produced by the first punch.

Figure l is similar to Figure 6 except thatav plete apparatus embodying the principles of my invention is illustrated in Figure 1. It consists of a bottom plate li and a top plate l=2,between l which, the various parts comprising'my invention are mounted. The tube being cut isrigidly A held between dies or jaws I3 and I4 in a'nutn the drawings.

ner more particularly shown i-n Figure on the drawings wherein the tube being cut is shown in cross section at I6. The die I3 is supported by a block I1 which is rigidly attached to the bleek zo, said mock 2o beig s1ideb1y attached to the bottom plate II as'shown in Figure 8 of Directly in front of die I4 `is another similar die I5. The block 20 is held on the bottom plate II by means of angle blocks shown at 2| and 22 these blocks being si, placed that the block 20 may freely move toward and away from the tube being cut, and in a line at right angles to the said tube. Mounted in the block 20 are two bearing blocks 24 and 25 which provide bearing surfaces for the metal block 26 which is rigidly supported on the top plate I2 and which passes through the block 20 and through a hole 21 in the bottom plate I I, thereby contacting the blocksl 24 and 25.

The lower end of block 28 is provided with an angular bearing surface or cam 28 which is designed to cooperate with a similar angular surface or cam 30 on the block 25.

A punch or cutter 3| is rigidly attached to block 32 which, in turn, is supported by the top plate I2. A second punch or cutter 34 is slidably mounted in a groove 35 and is rigidly attached to a sliding metallic block 36 which is vadapted to slide in a space between the block .I1 and a cover 31 attached across the top of the block I1. The cutting end of the punch 34 is provided with a bevelled end as shown at 95, at one end of which is a cutting edge as shown at 18. The punch 34 is provided with two parallel sides as shown at 99 and 91 and two additional cutting edges occur at 11 and 19 where the said parallel sides 96 and 91 intersect the bevelled end 95. The cutting edge 'I8 occurs where the said bevelled end 95 intersects bottom surface 92 of punch 34. e

Attached to the top plate I2 is a double cam member 39 which extends through a hole at 40 inthe sliding block4 36, through a hole at 4I in the block I1, and a hole 42 in the bottom plate ii. Within the hole 4I, and attached to the block I1 are two metallic bearing blocks 44 =and 45 which act as guidesfor the double cam member 39. The top plate I2 and the bottom plate II are held in proper register by 'a plurality of posts, preferably two, one of which is shown at as. The pest gasfisrigidly held in e hele 4s in bottom plate il, slides within a sleeve 99 which is rigidly set in the top plate I 2. A similar post is attached ina hole 49 in the bottom plate II, and slides in a sleeve 41 which is set in the top plate I2.

'I'he four dies, I3, I4, I5and I8 are shown more in detail in Figures 4 and 5. Figure 4 is a top plan view showing all four of these dies assembled together as they occur in the preferred modification of my apparatus shown in Figure 1 of the drawings when the punching operations rare made, and with a piece of metal tubing in posicut is shown at I6. The tubing to be cut is also shown in Figure 4 at I6, in position to be cut and tightly held at one side of the point of cutting, shown at 58, by the dies I3 and I4 and at the other side of said point of cutting by dies I5 and I8.

One shape of punch 3|, suitable for use 'in my invention is shown at IOI in Figure 6 wherein the tube I6 has already had one side cut away by the punch 34, leaving a hole in which has been inserted the end of the punch IOI. The angle AOB must be greater than degrees. The exact size of the angle AOB for best results will vary somewhat with the size, thickness of material, and nature of the material of which the tube I6 is made. However, I have found that a value of degrees will be entirely satisfactory and in most cases' preferable. However, angles as'small as 95 degrees and as great as 115 degrees will still be operative. The angle AOB may increase to much more than degrees as the punch is forced further and further into the tube. However it should be at least 95 degrees when punch I0! first contacts the tube I6 in order to insure a sufiicient outward thrust against the edge.

'I'he purpose of .keeping angle AOB greater than 90 degrees is to force the cut away portion, otherwise called the slug, of the tube I6 outwardly rather than forcing it into the inside of the tube. As' long as this cut away portion is be- -ing forced outwardly the edge |02 of the punch edges shown at 6I and |02. The end |03 and |04 of either modification of my punch should have cutting edges suitable for cooperating with the edges 50, 5I, 51, and 62 of dies I3, I4, I5 and I8 to cut out the lower half of the tube I6.

The exact shape of the end of the punches shown at 3| and IIlI is not extremely material as long as the force exerted to drive the punch 3| or IOI into the inside of the tube has an outward, positive component tending to force the edge of the tube contacting the punch 3| or IOI outwardly and against the edges 50, 5I, 51, and 62 of the dies I3, I4, I5, and I8.

At Figure 8 is shown a cross section of the metal block 20 and the dies I4 and I5, the ,angle bloclns 2| and 22 and -a portion of the bottom plate I I. The block 20 has holes drilled at 63. 64, 05, and 68 containing compression coil springs shown in cross section at 1I, 12, 13, and 14. Each of said'coil springs bear against block I1 and exert a forcetending to drive blocks I1 and 20 apart.

A detail of the cutting end of punch 34 is shown in Figure 9, the punch 34 is beveled as shown at 16 producing three straight, cutting edges as shown at 11, 18, and 19. In the preferred modification of my invention, the cutting edges 11 and 19 have angles of substantially 90 each, while the cutting edge 18 has an angle of about 45, though this latter angle may vary within wide limits depending on .the material being cut and the angle at which the knife 34 contacts the tube I6. Especially when cutting thickwalled tubing,

it is desirable to have the cutting edge 18, have an angle substantially greater than 45 more nearly approaching 90. 'Ihis may best be done by. rounding the edge 'I8 as is shown at III to produce this desired angle.

To cut a piece of metallic tubing with my apparatus, the apparatus is placed in a suitable punch press, the plates II and I2 being lattached to the press. 'Ihe top plate I2 is elevated toa point at which the cam surface 8l of the double cam 39 is above the cam Isurface 82 on the sliding metal blocks 36, and a cam surface 28 is punch 3|. will be i-n a position above the dies I3, I4, I5 and I8 so that the piece of tubing to be cut may be readily shoved through the-hole formed by the grooves 54 and 55 'which extend v above a cam surface 30 on the bearing block ,Y 3 tire mechanism is/in its original position. Thereafter the tubing mayl be removed or one of the pieces of tubing maybe placed inv another positionwithin the 'dies for making a further cut, as may be desired. 'l

The depth of the opening 86 is not extremely enter. It may be much deeper. However, if it is too deep, so that the punch 34 strikes the tube I8, from a direction too near in line with a along the edges of blocks I3, I4, I5 and I8 as y stated above. The tube is so placed that the point at which it is desired that it should be out is in the opening |05 between the'dies I3, I4,

I5, and I8. vThen, pressure is. exerted'on the,

top plate I2 forcing it toward the bottomplate II'. 'I'he rst action which takes place is that the cam surface 28 contacts the cam surface 3 0. thereby forcing the bearing block and the block 20 and the dies I4 and I5 ina direction toward the dies I3 and I8 and into a position where the dies I4 and I5 contact the dies I3 and I8, at which point the tube I6 is firmly held between the dies I3, I4, I5 and I8. As the downward movement of the top plate I2 continues, the

bearing surface 8| of the double cam 38 contacts the cam surface 82 of the block 36, thereby forcing said block 36 toward the tube I6, and at the same time forcing the punch 34 against the outer surface of the tube I6 as shown in Figure 5. As this movement ofpunch 34 continues the said punch is forced into, and finally through the Atube I6, cutting off a portion of said tube as shown in Figures 6 and 7. Then, as the downward movement of the topplate I2 continues further, a cam surface 84 contacts a cam surfacey 85.

thereby forcing the block as and the punch :uv

to theleft and away from the tube I6. As soon as the punch 34 is clear of the path of the punch 3|, the said punch 3| enters the opening88 in the tube I Ii as shown in the F1gures`6 and 7. As the punch 3| and top plate I2 descends still further, the edges 81 and 88 of the tube I8v are forced outwardly and are cut away from the remainder of the tube by a shearing action and nally, the lower portion of the tube is punched out, thereby severing the tube.

After the tube I6 has been severed, the top plate I2 is raised by the punch press during which changes occur as follows: A cam surface 88 on the double cam 38 contacts a cam surface 88.

on the metal block 36 forcing the block toward the tube I6 a second time. Thereafter a cam surface 90 on the double cam 38 contacts a cam surface 8| on the block v38 and forces the said block 3'6 back to its original position. After that, as the top plate I2 is raised still further the block 20 is released by the cam surface 28 rising to a point where it again contacts the cam surface 30 on bearing surface 25, thereby allowing the springs -1I, 12, 13. and 14 to force the block 20 to the right, thereby opening the dies or jaws I3, I4,- I5, and I8. At this point the en- 34, to make an opening large enough to admit' the second punch 3ll in the manner explained above without causing the tube I8 ,to collapse.

While the above processland apparatus' have been described and 'illustrated as cutting round tubing,'it will be understood thatthe apparatus may be modified so as to cut elliptical, square,

triangular, pentagonal, hexagonal and similar shapes of tubing, without departing from thev I broad principles of this invention.

It will also be evident that the tube does not have to be cut square across, but that the cut may be made at a Vvariety of angles, and also that Ithe cut does not need to be made ina plane, but that'the punches and dies may be so shaped that the cut may be a portion of a cylinder, or similaicylin- Thus it will be seen that I have-deviseda new and improved method and apparatus for cutting i metal and similar tubing wherein the cut Ican be made at any distance fromthe ends of the tube, and without inserting a plug die o r any other device into the interior of the tube through the ends thereof, and without leaving any rougherfied or uneven surface at the cut Vends thereo l It will be evident that this apparatus and process is not limited to the cutting of metallic tubingfbut may be used for cutting of tubing made of other materials.

I am aware that numerous details of construction may be varied through a wide range without departing from the principles of this invention and I, therefore, do not purpose limiting the patents granted hereon otherwise necessitated by the prior art.

I claim as my invention:

1. A tube cutting mechanism comprising separable jaws for enclosing atube around the periphery of the same, and tightly holding the tube, cutting means exterior to said tube and adjacent said -jaws for cutting a slot in the tube, means for entering said slot and exerting an outward shearing stress against the walls of the tube along the interior of the tube adjacent the line, of contact of said jaws with the tube whereby'the tube will punch means having substantially the same thickness as the distance along said tube separating-said two diameters, a slot in said first mentioned means exposing the portion of said tube between said two diameters, means for forcing said punch means into said slot, against said tube, and completely through said tube and out the opposite side thereof, thereby cutting away a portion of said tube, a second punch means having substantially the same thickness as said first mentioned punch means, and having a constantly increasing width, and means for forcing said second punch means into the hole in said tube resulting from the operation of said firstpunch means and completely through said tube thereby severing the same, the contour Vof the edge of said second punch means being such that the exterior angle made by said edge with the edge of said tube at the point of contact therewith is in excess of ninety degrees until said punch has been forced half way through said tube.

3. A device for cutting a tube, comprising a separable die means fitting tightly around the outside of the tube to be cut, a groove in said die means, a cutter operating along said groove and along a secant line across the section of the tube to be cut, means for forcing said cutter along said groove and into and through the tube along said secant line and means for returning said 'cutter to its original position thereby forming a hole in the tube, a second cutter, having one Wide and one narrow end, cutting edges on said die means and exterior to said tube to cooperate with said cut-v ters, and means for forcing the narrow end of ,said second cutter into the hole formed by said first mentioned cutter.

4. A device for cutting a tube, comprising a separable die means fitting tightly around the outside of the tube at the point to be cut, a groove in said die means, a cutter operating along said groove and along a secant line across the section of the tube to be cut, and means for forcing said cutter along said groove and into and through the tube to be cut,.along said secant line to cut a slot into the tube, a second cutter, having a width greater than the tube, means for forcing said second cutter into said opening and completely through the tube, arcuaate cutting edges on said second cutter, said edges being so proportioned as to form an external angle of at least' 95 and not along said secant line, a second opening in said jaws which intersects said slot and said opening, a second cutter operating through said second fopening, and means for forcing said second cutter through said tube, into said second opening and through the tube to be cut.

7. -A tube cutting device comprising two sets of separable jaws external to said tube to support said tube against distortion and rotation at two perimeters thereof, a space between said sets of jaws, a cutter operating in said space and'alonga secant line across a section of the tube to be cut at the point of cutting, means for moving said cutter along the secant line, to cut an opening into said tube, a second cutter operating in said space in a direction substantially at right angles to said secant line and in line with said opening made by said first cutter and means to move said second cutter into and out of said opening.

8. In an apparatus for cutting metal tubing, a combination comprising separable jaws for supporting' the tube exteriorly at the point of cutting and two punches operating substantially at right angles to each other, means for guiding one of said punchesv against said tube to strike a glancing blow thereon whereby a hole is cut in said tube, and means for guiding the other of said punches into said hole and completely through said tube at the point of cutting, thereby cutting the tube into two pieces.

9. In an apparatus for cutting tubing, separable jaws for supporting a tube exteriorly around a. periphery at the point of cutting the tube, said jaws forming a surface when in closed position,

said surface intersecting the tube at the point of cutting, a cutter moving upon said surface and traversing a segment of the cross section of the tube at the point of cutting, thereby cutting a hole in the tube. a second cutter moving upon more than 115 with the tube at the ends of said slot until the said second cutter has been forced halfway through the tube.

5. A tube cutting mechanism comprising a set of separable jaws for holding a tube, surfaces on said jaws conforming to the shape of a tube to be cut, cam means for opening and closing said jaws, a slot in said jaws, a cutter operating in said slot, a second cam means for 'forcing said cutter along said slot and against and into the tube, and cutting a hole into the tube, a third cam meansfor forcing said cutter back to its original position, a second slot in said jaws, and

a second cutter operating in said second slot and cam means for forcing said second mentioned cutter along said second mentioned slot and into the hole formed in the tube by lsaid first :nentioned cutter and completely through the tube, thereby severing the same.

6. A device for cutting a tube comprising a set of separable jaws adapted to fit around a tube to be cut, surfaces on said jaws conforming to the shape of a tubetto be cut, means for. opening and closing said jaws. grooves in said jaws to form an opening the size of the tube to be cut, when said jaws are in closed position, a slot in said jaws crossing and making a secant line with said opening, a cutter operating in said slot, means for forcing said cutter through the tube to be cut said surface substantially atright angles to the direction of motion of said first mentioned cutter, and entering the hole cut by said first mentioned cutter and traversing the entirety of said cross section, thereby severing said tube.

10. A device for cutting a tube, comprising sep: arable jaws for holding a tube to be cut at the point of cutting, a groove in said jaws, a cutter operating in said groove, and along a secant line across the section of the tube to be cut at the point of cutting and across a segment of said section, and a cutting edge on an end of `said cutter, means for forcing said cutting edge along said secant line, a second groove in said jaws, a second cutter operating in said second groove in a direction substantially at right angles to said first cutter, a cutting edge on an end of said second mentioned cutter, said second mentioned cutter having a substantially constant thickness and a width which decreases toward said end, cutting edges along the sides of said cutter, and means for forcing said first mentioned cutter along said first mentioned groove and through the tube to be cut, whereby an arcuate hole is formed therein, and means for withdrawing the said first mentioned cutter. and means for moving said second mentioned cutter into the hole formed by said rocating said cutters alternately whereby one cutter makes its cutting stroke in advance of the other cutter.

12. A tube cutting mechanism comprising two sets of separable jaws, surfaces on said jaws conforming to the shape of a tbe to be cut for grasping a tube around its periphery at two places, one on each side of the point of cutting, a cutter'operating between said two sets of jaws, means for forcing said cutter through the side of the tube and through the opposite side thereof, at an angle sufficiently acute so that the hole of entry and the hole of exit of said cutter are connected, a

punch wider than the diameter of the tube, andV means for withdrawing said cutter and means for forcing said punch into the hole produced by said cutter, and forcing said punch completely through the tube, thereby severing the same.

13. A tube cutting mechanismcomprising separable jaws having surfaces conforming to the shape of a tube to be cut, means for closing said jaws around the tube to be cut, and tightly holding the same, a cutter exterior to said tube and adjacent said jaws, means for forcing said cutter against and through said tube whereby a slot is cut in said tube, a second cutter, and means for forcing said second `cutter into said slot and against the interior of said tube adjacent the line of contact of said jaws with said tube and exerting a shearing stress on said tube along said line, thereby severing said tube.

14. A tube cutting mechanism comprising a set of dies for holding a tube to be cut, each of said dies having one plane surface, a groove in each of said diestraversing said plane surface and conforming to the shape of the tube to be cut, means for slidablysupporting one of said dies, means for `sliding said die awayrfrom the other of said dies thereby enlarging the opening between said dies formed by said grooves, means for closing said y dies upon a tube to be cut at the point of cutting,

\and.two punches operating at angles to each for guiding the other of said punches into said hole and completely through said tube, thereby cutting the tube into two pieces.

FRED GRIEDER. 

